By Medically reviewed by hellodoktor

Generic Name: Tolbutamide Brand Name(s): Generics only. No brands available.


What is Tolbutamide used for?

Tolbutamide is used with a proper diet and exercise program to control high blood sugar in people with type 2 diabetes. It may also be used with other diabetes medications. Controlling high blood sugar helps prevent kidney damage, blindness, nerve problems, loss of limbs, and sexual function problems. Proper control of diabetes may also lessen your risk of a heart attack or stroke. Tolbutamide belongs to the class of drugs known as sulfonylureas. It works by causing the release of your body’s natural insulin and may help to restore your body’s proper response to insulin.

How should I take Tolbutamide?

Take this medication by mouth as directed by your doctor, usually once daily in the morning. Your daily dose may also be divided into smaller doses to be taken several times a day, especially if this medication causes stomach upset. Follow your doctor’s instructions carefully. The dosage is based on your medical condition and response to treatment.

To reduce your risk of side effects, your doctor may direct you to start this medication at a low dose and gradually increase your dose. Follow your doctor’s instructions carefully.

If you are already taking another diabetes drug (such as chlorpropamide), follow your doctor’s directions carefully for stopping the old drug and starting tolbutamide.

Use this medication regularly to get the most benefit from it. To help you remember, take it at the same time(s) each day.

Tell your doctor if your condition does not improve or if it worsens (your blood sugar is too high or too low).

How do I store Tolbutamide?

Tolbutamide is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store Tolbutamide in the bathroom or the freezer. There may be different brands of Tolbutamide that may have different storage needs. It is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush Tolbutamide down the toilet or pour them into a drain unless instructed to do so. It is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Precautions & warnings

What should I know before using Tolbutamide?

Before taking tolbutamide, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney disease, liver disease, low sodium blood level (hyponatremia), certain hormonal conditions (adrenal/pituitary insufficiency, thyroid disease, syndrome of inappropriate antidiuretic hormone-SIADH).

You may experience blurred vision, dizziness, or drowsiness due to extremely low or high blood sugar. Do not drive, use machinery, or do any activity that requires alertness or clear vision until you are sure you can perform such activities safely.

Limit alcohol while taking this medication because it can increase your risk of developing low blood sugar. Rarely, alcohol can interact with tolbutamide and cause a serious reaction (disulfiram-like reaction) with symptoms such as facial flushing, nausea, vomiting, dizziness, or stomach pain. Consult your doctor or pharmacist about the safe use of alcohol.

It may be harder to control your blood sugar when your body is stressed (such as due to fever, infection, injury, or surgery). Consult your doctor because this may require a change in your treatment plan, medications, or blood sugar testing.

This medication may make you more sensitive to the sun. Limit your time in the sun. Avoid tanning booths and sunlamps. Use sunscreen and wear protective clothing when outdoors. Tell your doctor right away if you get sunburned or have skin blisters/redness.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Older adults may be more sensitive to the side effects of this drug, especially low blood sugar.

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

Pregnancy may cause or worsen diabetes. Discuss a plan with your doctor for managing your blood sugar while pregnant. Your doctor may change your diabetes treatment during your pregnancy (such as diet and medications including insulin).

This medication passes into breast milk. Consult your doctor before breast-feeding.

Is it safe during pregnancy or breast-feeding?

There are no adequate studies in women for determining risk when using this Tolbutamide during pregnancy or while breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking Tolbutamide. Tolbutamide is pregnancy risk category C according to the US Food and Drug Administration (FDA).

FDA pregnancy risk category reference below:

  • A=No risk,
  • B=No risk in some studies,
  • C=There may be some risk,
  • D=Positive evidence of risk,
  • X=Contraindicated,
  • N=Unknown

Side effects

What side effects can occur from Tolbutamide?

Stomach upset/fullness, nausea, headache, and weight gain may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including: dark urine, easy bleeding/bruising, persistent nausea, severe stomach/abdominal pain, signs of infection (such as persistent sore throat, fever), yellowing eyes/skin.

This medication can cause low blood sugar (hypoglycemia). This may occur if you do not consume enough calories from food or if you do unusually heavy exercise. Symptoms of low blood sugar include sudden sweating, shaking, fast heartbeat, hunger, blurred vision, dizziness, or tingling hands/feet. It is a good habit to carry glucose tablets or gel to treat low blood sugar. If you don’t have these reliable forms of glucose, rapidly raise your blood sugar by eating a quick source of sugar such as table sugar, honey, or candy, or drink fruit juice or non-diet soda. Tell your doctor right away about the reaction and the use of this product. To help prevent low blood sugar, eat meals on a regular schedule, and do not skip meals. Check with your doctor or pharmacist to find out what you should do if you miss a meal.

Symptoms of high blood sugar (hyperglycemia) include thirst, increased urination, confusion, drowsiness, flushing, rapid breathing, and fruity breath odor. If these symptoms occur, tell your doctor right away. Your dosage may need to be increased.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

Not everyone experiences these side effects. There may be some side effects not listed above. If you have any concerns about a side-effect, please consult your doctor or pharmacist.


What drugs may interact with Tolbutamide?

Beta-blocker medications (including metoprolol, propranolol, glaucoma eye drops such as timolol) may prevent the fast/pounding heartbeat you would usually feel when your blood sugar falls too low (hypoglycemia). Other symptoms of low blood sugar such as dizziness, hunger, or sweating are unaffected by these drugs.

Check the labels on all your medicines (such as cough-and-cold products) because they may contain ingredients that could affect your blood sugar. Ask your pharmacist about using those products safely.

This medication may interfere with certain laboratory tests, possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug.

Tolbutamide may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs and herbal products) and share it with your doctor and pharmacist. For your safety, do not start, stop, or change the dosage of any drugs without your doctor’s approval.

Does food or alcohol interact with Tolbutamide?

Tolbutamide may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

What health conditions may interact with Tolbutamide?

Tolbutamide may interact with your health condition. This interaction may worsen your health condition or alter the way the drug works. It is important to always let your doctor and pharmacist know all the health conditions you currently have.


The information provided is not a substitute for any medical advice. You should ALWAYS consult with your doctor or pharmacist before using this Tolbutamide.

What is the dose of Tolbutamide for an adult?

Usual Adult Dose for Diabetes Type 2

Initial dose: 1 to 2 g orally once a day or in divided doses through the day

-Adjust dose based on blood glucose response

Maintenance dose: 0.25 to 3 g orally once a day or in divided doses through the day

Maximum dose: 3 g per day

Comments: Transferring patients from other oral antidiabetic regimens should be done conservatively:

-When transferring from chlorpropamide, particular care should be exercised during the first 2 weeks due to the potential for overlapping hypoglycemic effects.

-When transferring from insulin therapy, concurrent insulin therapy should be maintained in patients requiring 20 units of insulin/day or more:

–Patients requiring 20 to 40 units of insulin/day should have insulin reduced by 30% to 50% for the first few days, and then adjust therapy based on response.

–Patients requiring more than 40 units of insulin/day should have insulin reduced by 20% the first day, and then adjust therapy based on response.

Use: As an adjunct to diet to lower blood glucose in patients with type 2 diabetes whose hyperglycemia cannot be controlled by diet alone.

Renal Dose Adjustments

Use with caution; initial and maintenance dosing should be conservative to avoid hypoglycemic reactions.

Liver Dose Adjustments

Use with caution; initial and maintenance dosing should be conservative to avoid hypoglycemic reactions.

Dose Adjustments

Elderly, debilitated, or malnourished patient: Initial and maintenance dosing should be conservative to avoid hypoglycemic reactions.

Other Comments

Administration advice:

Take orally once a day in the morning or in divided doses through the day

Storage requirements:

-Protect from light


-Hypoglycemia may occur, especially in the elderly, debilitated, or malnourished patient, in patients receiving combination therapy, and/or those with renal, hepatic or adrenal insufficiency; dose reduction of this drug may be necessary.

-This drug should not be used in patients with type 1 diabetes mellitus or diabetic ketoacidosis.

-Hemolytic anemia may occur in glucose 6-phosphate dehydrogenase (G6PD) deficient patients; consider a non-sulfonylurea alternative.

-When a patient stabilized on any diabetic regimen is exposed to stress such as fever, trauma infection, or surgery, it may be necessary to stop this drug and administer insulin.


Regular clinical and laboratory evaluations are necessary to determine minimum effective dose and detect primary or secondary failure.

-Clinical status should be checked within the first 4 to 8 weeks and regularly, thereafter

-Laboratory monitoring including periodic fasting blood glucose, self-monitoring of blood glucose, and urine testing (i.e., glucose and ketones) should be done more frequently during drug initiation and with changing doses; glycosylated hemoglobin levels (HbA1c) should be done as clinically warranted.

Patient advice:

-Patients should understand the importance of exercise and dietary control in the management of their disease.

-Patients should understand that alcohol ingestion, intense or prolonged exercise, skipping meals, illness, or lifestyle changes may increase their risks for hypoglycemia; they should know how to recognize the symptoms of hypoglycemia and be prepared to treat it.

-Patients should be careful about driving and use of machinery, especially when at risk for hypoglycemia.

-Patients should speak with their health care provider during periods of stress such as fever, trauma, or illness, as their diabetes management may need to be changed.

-Advise patient to speak to physician or health care professional if pregnant, intend to become pregnant, or are breastfeeding.

What is the dose of Tolbutamide for a child?

The dosage has not been established in pediatric patients. It may be unsafe for your child. It is always important to fully understand the safety of the drug before using. Please consult with your doctor or pharmacist for more information.

How is Tolbutamide available?

Tolbutamide is available in the following dosage forms and strengths:

  • Oral tablet,
  • Intravenous powder for injection.

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, call your local emergency services or go to your nearest emergency room.

What should I do if I miss a dose?

If you miss a dose of Tolbutamide, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.

Hello Health Group does not provide medical advice, diagnosis or treatment.

Review Date: June 2, 2018 | Last Modified: September 12, 2019

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